from __future__ import annotations

import math
import tempfile
from dataclasses import dataclass
from pathlib import Path
from typing import Iterable

import numpy as np
import trimesh
from scipy import ndimage
from skimage import measure

from llm_parser import DEFAULT_LOCAL_MODEL, parse_prompt_with_local_llm
from parser import PromptSpec, parse_prompt


@dataclass
class BuildArtifacts:
    ply_path: str
    glb_path: str
    summary: dict


SCALE_FACTORS = {
    "small": 1.0,
    "medium": 1.35,
    "large": 1.85,
}


def _sample_box_surface(center, size, density: int, label: int) -> tuple[np.ndarray, np.ndarray, np.ndarray]:
    cx, cy, cz = center
    sx, sy, sz = size
    n = max(4, density)
    u = np.linspace(-0.5, 0.5, n)
    vv = np.linspace(-0.5, 0.5, n)
    pts = []
    normals = []
    labels = []
    for ax in (-1, 1):
        x = np.full((n, n), cx + ax * sx / 2)
        y, z = np.meshgrid(u * sy + cy, vv * sz + cz)
        pts.append(np.column_stack([x.ravel(), y.ravel(), z.ravel()]))
        normals.append(np.tile([ax, 0, 0], (n * n, 1)))
        labels.append(np.full(n * n, label))
    for ay in (-1, 1):
        y = np.full((n, n), cy + ay * sy / 2)
        x, z = np.meshgrid(u * sx + cx, vv * sz + cz)
        pts.append(np.column_stack([x.ravel(), y.ravel(), z.ravel()]))
        normals.append(np.tile([0, ay, 0], (n * n, 1)))
        labels.append(np.full(n * n, label))
    for az in (-1, 1):
        z = np.full((n, n), cz + az * sz / 2)
        x, y = np.meshgrid(u * sx + cx, vv * sy + cy)
        pts.append(np.column_stack([x.ravel(), y.ravel(), z.ravel()]))
        normals.append(np.tile([0, 0, az], (n * n, 1)))
        labels.append(np.full(n * n, label))
    return np.vstack(pts), np.vstack(normals), np.concatenate(labels)


def _sample_ellipsoid_surface(center, radii, density: int, label: int) -> tuple[np.ndarray, np.ndarray, np.ndarray]:
    cx, cy, cz = center
    rx, ry, rz = radii
    nu = max(16, density * 3)
    nv = max(10, density * 2)
    u = np.linspace(0, 2 * math.pi, nu, endpoint=False)
    v = np.linspace(-math.pi / 2, math.pi / 2, nv)
    uu, vv = np.meshgrid(u, v)
    x = cx + rx * np.cos(vv) * np.cos(uu)
    y = cy + ry * np.cos(vv) * np.sin(uu)
    z = cz + rz * np.sin(vv)
    pts = np.column_stack([x.ravel(), y.ravel(), z.ravel()])
    normals = np.column_stack([
        (x - cx).ravel() / max(rx, 1e-6),
        (y - cy).ravel() / max(ry, 1e-6),
        (z - cz).ravel() / max(rz, 1e-6),
    ])
    normals /= np.linalg.norm(normals, axis=1, keepdims=True) + 1e-8
    labels = np.full(len(pts), label)
    return pts, normals, labels


def _sample_cylinder_surface(center, radius, length, axis: str, density: int, label: int) -> tuple[np.ndarray, np.ndarray, np.ndarray]:
    cx, cy, cz = center
    nt = max(18, density * 4)
    nl = max(6, density)
    theta = np.linspace(0, 2 * math.pi, nt, endpoint=False)
    line = np.linspace(-length / 2, length / 2, nl)
    tt, ll = np.meshgrid(theta, line)
    if axis == "x":
        x = cx + ll
        y = cy + radius * np.cos(tt)
        z = cz + radius * np.sin(tt)
        normals = np.column_stack([np.zeros(x.size), np.cos(tt).ravel(), np.sin(tt).ravel()])
    elif axis == "y":
        x = cx + radius * np.cos(tt)
        y = cy + ll
        z = cz + radius * np.sin(tt)
        normals = np.column_stack([np.cos(tt).ravel(), np.zeros(x.size), np.sin(tt).ravel()])
    else:
        x = cx + radius * np.cos(tt)
        y = cy + radius * np.sin(tt)
        z = cz + ll
        normals = np.column_stack([np.cos(tt).ravel(), np.sin(tt).ravel(), np.zeros(x.size)])
    pts = np.column_stack([x.ravel(), y.ravel(), z.ravel()])
    labels = np.full(len(pts), label)
    return pts, normals, labels


def build_particle_blueprint(
    prompt: str,
    detail: int = 24,
    parser_mode: str = "heuristic",
    model_id: str | None = None,
) -> tuple[np.ndarray, np.ndarray, np.ndarray, PromptSpec, str]:
    parser_mode = (parser_mode or "heuristic").strip().lower()
    parser_backend = "heuristic"
    if parser_mode.startswith("local"):
        spec = parse_prompt_with_local_llm(prompt, model_id=model_id or DEFAULT_LOCAL_MODEL)
        parser_backend = f"local_llm:{model_id or DEFAULT_LOCAL_MODEL}"
    else:
        spec = parse_prompt(prompt)
    scale = SCALE_FACTORS[spec.scale]
    density = max(6, detail)

    parts = []
    normals = []
    labels = []

    hull_len = 2.8 * scale
    hull_w = 1.2 * scale
    hull_h = 0.8 * scale

    if spec.hull_style == "rounded":
        p, n, l = _sample_ellipsoid_surface((0.0, 0.0, 0.0), (hull_len / 2, hull_w / 2, hull_h / 2), density, 0)
    elif spec.hull_style == "sleek":
        p1, n1, l1 = _sample_ellipsoid_surface((0.12 * scale, 0.0, 0.0), (hull_len / 2.3, hull_w / 2.8, hull_h / 2.6), density, 0)
        p2, n2, l2 = _sample_box_surface((-0.15 * scale, 0.0, -0.02 * scale), (hull_len * 0.52, hull_w * 0.5, hull_h * 0.55), density // 2, 0)
        p = np.vstack([p1, p2])
        n = np.vstack([n1, n2])
        l = np.concatenate([l1, l2])
    else:
        p, n, l = _sample_box_surface((0.0, 0.0, 0.0), (hull_len, hull_w, hull_h), density, 0)
    parts.append(p)
    normals.append(n)
    labels.append(l)

    cockpit_center = (hull_len / 2 - hull_len * spec.cockpit_ratio * 0.8, 0.0, hull_h * 0.14)
    cp, cn, cl = _sample_ellipsoid_surface(cockpit_center, (hull_len * spec.cockpit_ratio, hull_w * 0.22, hull_h * 0.24), density // 2, 1)
    parts.append(cp)
    normals.append(cn)
    labels.append(cl)

    if spec.cargo_ratio > 0.16:
        cargo_center = (-hull_len * 0.18, 0.0, -hull_h * 0.06)
        cargo_size = (hull_len * spec.cargo_ratio, hull_w * 0.76, hull_h * 0.6)
        pp, pn, pl = _sample_box_surface(cargo_center, cargo_size, density // 2, 2)
        parts.append(pp)
        normals.append(pn)
        labels.append(pl)

    if spec.wing_span > 0:
        wing_length = hull_len * 0.34
        wing_width = hull_w * 0.18
        wing_height = hull_h * 0.08
        yoff = hull_w * 0.45 + wing_width * 0.6
        for side in (-1, 1):
            wc = (-0.1 * scale, side * yoff, -0.04 * scale)
            pp, pn, pl = _sample_box_surface(wc, (wing_length, wing_width, wing_height), max(6, density // 3), 3)
            parts.append(pp)
            normals.append(pn)
            labels.append(pl)

    engine_radius = 0.14 * scale if spec.object_type != "fighter" else 0.1 * scale
    engine_length = 0.48 * scale
    engine_y_positions = np.linspace(-hull_w * 0.32, hull_w * 0.32, spec.engine_count)
    for ypos in engine_y_positions:
        ec = (-hull_len / 2 + engine_length * 0.3, ypos, 0.0)
        pp, pn, pl = _sample_cylinder_surface(ec, engine_radius, engine_length, "x", max(6, density // 3), 4)
        parts.append(pp)
        normals.append(pn)
        labels.append(pl)

    if spec.fin_height > 0:
        fin_center = (-hull_len * 0.25, 0.0, hull_h * 0.42)
        fin_size = (hull_len * 0.18, hull_w * 0.1, hull_h * max(spec.fin_height, 0.12))
        pp, pn, pl = _sample_box_surface(fin_center, fin_size, max(6, density // 3), 5)
        parts.append(pp)
        normals.append(pn)
        labels.append(pl)

    if spec.landing_gear:
        gear_x = np.array([-hull_len * 0.18, hull_len * 0.12])
        gear_y = np.array([-hull_w * 0.28, hull_w * 0.28])
        for gx in gear_x:
            for gy in gear_y:
                gc = (gx, gy, -hull_h * 0.45)
                pp, pn, pl = _sample_cylinder_surface(gc, 0.04 * scale, 0.22 * scale, "z", max(5, density // 5), 6)
                parts.append(pp)
                normals.append(pn)
                labels.append(pl)

    points = np.vstack(parts)
    point_normals = np.vstack(normals)
    point_labels = np.concatenate(labels)

    if spec.asymmetry > 0:
        mask = points[:, 1] > 0
        points[mask, 2] += spec.asymmetry * np.sin(points[mask, 0] * 2.0)

    return points.astype(np.float32), point_normals.astype(np.float32), point_labels.astype(np.int32), spec, parser_backend


def points_to_mesh(points: np.ndarray, pitch: float = 0.08, padding: int = 5, sigma: float = 1.2, level: float = 0.11) -> trimesh.Trimesh:
    mins = points.min(axis=0) - padding * pitch
    maxs = points.max(axis=0) + padding * pitch
    dims = np.ceil((maxs - mins) / pitch).astype(int) + 1
    dims = np.clip(dims, 24, 192)

    grid = np.zeros(tuple(dims.tolist()), dtype=np.float32)
    coords = ((points - mins) / pitch).astype(int)
    coords = np.clip(coords, 0, dims - 1)
    np.add.at(grid, (coords[:, 0], coords[:, 1], coords[:, 2]), 1.0)

    grid = ndimage.gaussian_filter(grid, sigma=sigma)
    verts, faces, normals, _ = measure.marching_cubes(grid, level=level)
    verts = verts * pitch + mins

    mesh = trimesh.Trimesh(vertices=verts, faces=faces, vertex_normals=normals, process=True)
    mesh.update_faces(mesh.nondegenerate_faces())
    mesh.update_faces(mesh.unique_faces())
    mesh.remove_unreferenced_vertices()
    try:
        mesh.fill_holes()
    except Exception:
        pass
    try:
        trimesh.smoothing.filter_humphrey(mesh, iterations=2)
    except Exception:
        pass
    return mesh


def export_point_cloud_as_ply(points: np.ndarray, labels: np.ndarray, path: str) -> str:
    colors = np.array([
        [170, 170, 180],
        [120, 180, 255],
        [255, 190, 120],
        [180, 180, 255],
        [255, 120, 120],
        [200, 255, 180],
        [255, 255, 180],
    ], dtype=np.uint8)
    c = colors[labels % len(colors)]
    pc = trimesh.points.PointCloud(vertices=points, colors=c)
    pc.export(path)
    return path


def export_mesh_as_glb(mesh: trimesh.Trimesh, path: str) -> str:
    mesh.visual.vertex_colors = np.tile(np.array([[185, 190, 200, 255]], dtype=np.uint8), (len(mesh.vertices), 1))
    mesh.export(path)
    return path


def run_pipeline(
    prompt: str,
    detail: int = 24,
    voxel_pitch: float = 0.08,
    parser_mode: str = "heuristic",
    model_id: str | None = None,
) -> BuildArtifacts:
    points, normals, labels, spec, parser_backend = build_particle_blueprint(
        prompt,
        detail=detail,
        parser_mode=parser_mode,
        model_id=model_id,
    )
    mesh = points_to_mesh(points, pitch=voxel_pitch)

    out_dir = Path(tempfile.mkdtemp(prefix="particle_blueprint_"))
    ply_path = str(out_dir / "blueprint.ply")
    glb_path = str(out_dir / "mesh.glb")
    export_point_cloud_as_ply(points, labels, ply_path)
    export_mesh_as_glb(mesh, glb_path)

    summary = {
        "prompt": prompt,
        "parser_backend": parser_backend,
        "spec": spec.to_dict(),
        "point_count": int(len(points)),
        "vertex_count": int(len(mesh.vertices)),
        "face_count": int(len(mesh.faces)),
        "bounds": mesh.bounds.round(3).tolist(),
        "voxel_pitch": voxel_pitch,
    }

    return BuildArtifacts(ply_path=ply_path, glb_path=glb_path, summary=summary)